<template>
    <div>
      <router-link
        tag="div"
        to="/"
        class="header-abs"
        v-show="showAbs"
      >
        <div
          class="iconfont
           header-abs-back">&#xe624;</div>
      </router-link>
      <div
        class="header-fixed"
        v-show="!showAbs"
        :style="opacityStyle"
      >
        <router-link tag="div" to="/" class="header-abs">
          <div class="iconfont header-fixed-back">&#xe624;</div>
        </router-link>
        景点详情
      </div>
    </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll: function () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  activated () {
    window.addEventListener('scroll',this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
  @import '~styles/varibles.styl'
  .header-abs
    position: absolute
    width: .8rem
    height: .8rem
    border-radius: .4rem
    background: rgba(0,0,0,.8)
    text-align: center
    line-height: .8rem
    top: .2rem
    left: .2rem
    right: .2rem
    .header-abs-back
      color: #ffffff
      font-size: .4rem
  .header-fixed
    position: fixed
    top: 0
    left: 0
    right: 0
    height: $headerHeight
    line-height: $headerHeight
    text-align: center
    color: #ffffff
    background: $bgColor
    font-size: .32rem
    .header-fixed-back
      position:absolute
      color: #ffffff
      top: 0
      left: 0
      width: .64rem
      text-align: center
      font-size: .4rem
</style>
